Compositions and methods for repair of aneurysms are described. In particular, completely or almost completely absorbable vaso-occlusive members are disclosed, as are methods of making and using these members.
An aneurysm is a dilation of a blood vessel (similar to a balloon) that poses a risk to health from the potential for rupture, clotting, or dissecting. Rupture of an aneurysm in the brain causes stroke, and rupture of an aneurysm in the abdomen causes shock. Cerebral aneurysms are usually detected in patients as the result of a seizure or hemorrhage and can result in significant morbidity or mortality.
There are a variety of materials and devices which have been used for treatment of aneurysms, including platinum and stainless steel microcoils, polyvinyl alcohol sponges (Ivalone), and other mechanical devices. For example, vaso-occlusion devices are surgical implements or implants that are placed within the vasculature of the human body, typically via a catheter, either to block the flow of blood through a vessel making up that portion of the vasculature through the formation of an embolus or to form such an embolus within an aneurysm stemming from the vessel. One widely used vaso-occlusive device is a helical wire coil having windings which may be dimensioned to engage the walls of the vessels. (See, e.g., U.S. Pat. No. 4,994,069 to Ritchart et al.) Other less stiff helically coiled devices have been described, as well as those involving woven braids.
U.S. Pat. No. 5,354,295 and its parent, U.S. Pat. No. 5,122,136, both to Guglielmi et al., describe an electrolytically detachable embolic device. Vaso-occlusive coils having little or no inherent secondary shape have also been described. For instance, co-owned U.S. Pat. Nos. 5,690,666 and 5,826,587 by Berenstein et al., describes coils having little or no shape after introduction into the vascular space.
Attempts to increase thrombogenicity of metal coils have also been attempted, for example by modifying the surface of the coil. WO 99/44538 discloses use of GDC coils coated with biodegradable polymers or proteins. U.S. Pat. No. 5,669,931 to Kupiecki discloses coils that may be filed or coated with thrombotic or medicinal material. U.S. Pat. No. 5,749,894 to Engleson discloses polymer coated vaso-occlusion devices. U.S. Pat. No. 5,690,671 to McGurk discloses an embolic element which may include a coating, such as collagen, on the filament surface. U.S. Pat. No. 5,536,274 to Neuss shows spiral implants, some of which are coated with metal particles, silicone, PTFE, rubber latices, or polymers. U.S. Pat. No. 5,980,550 describes a vaso-occlusive device having a bioactive inner coating and a water-soluble outer coating. Co-owned WO/027445, titled xe2x80x9cBioactive Coating for Vaso-occlusive Devices,xe2x80x9d describes vaso-occlusive devices coated with a collagen-based material and, additionally, describes the use of a tie-layer between the device and the collagen-based coating.
Liquid embolics, such as cyanoacrylate glues and fibrin sealants, have also been used in animal and human subjects. See, e.g., Interventional Radiology, Dandlinger et al, ed., Thieme, N.Y., 1990:295-313; Suga et al. (1992) No Shinkei Geka 20(8):865-873; Moringlane et al. (1987) Surg Neurol 28(5):361-366; Moringlane et al. (1988) Acta Neurochir Suppl. (Wein) 43:193-197. Of these liquid embolics, cyanoacrylate glues are the only liquid embolics currently available to neurosurgeons. However, chronic inflammation is typically seen with cyanoacrylate treatments (Herrera et al. (1999) Neurol Med Chir (Tokyo) 39(2):134-139) and the degradation product, formaldehyde, is highly toxic to the neighboring tissues. See, Vinters et al (1995) Neuroradiology 27:279-291. Another disadvantage of cyanoacrylate materials is that the polymer will adhere both to the blood vessel and to the tip of the catheter. Thus physicians must retract the catheter immediately after injection of the cyanoacrylate embolic material or risk adhesion of the cyanoacrylate and the catheter to the vessel.
WO 00/44306 discloses endovascular apparatuses comprising an at least partially absorbable polymeric or protein coil and a placement device.
None of these documents describe vaso-occlusive members having the characteristics described herein or methods of making such members.
Thus, this invention includes novel occlusive compositions as well as methods of using and making these compositions.
In one aspect, the invention includes an absorbable vaso-occlusive member comprising: (i) an absorbable material; and (ii) one or more stretch-resistant members fixedly attached to at least two locations of the absorbable material. Non-limiting examples of suitable absorbable materials include polyglygolic acid (PGA), poly-glycolic/poly-L-lactic acid co-polymers, polycaprolactone, polyhydroxybutyrate/hydroxyvalerate copolymers, poly-L-lactide, polydioxanone, polycarbonates, polyanhydrides, collagen, elastin, fibrinogen, fibronectin, vitronectin, laminin, gelatin and combinations thereof.
The vaso-occlusive members described herein can have any three-dimensional shape, including, for example, J-shaped, straight, cylindrical, spherical, tube-like, and helical coil. In certain embodiments, for example where the vaso-occlusive member is configured as a helical coil having a plurality of helical winds, a first end, a second end and lumen between said first and second ends, the stretch-resistant member extends through said lumen of the coil and is attached to said first and second ends. Alternatively, the stretch-resistant member can be threaded through holes, perforations or winds of the three-dimensional member (e.g., threaded through winds of a coil or through perforations of a tube). Furthermore, in any of the vaso-occlusive members described the stretch-resistant member can be attached to the interior or, alternatively, exterior of the members (e.g., helical coil or tube).
In certain embodiments, the stretch-resistant member is non-absorbable. In other embodiments, the stretch-resistant member is absorbable. For example, absorbable stretch-resistant members can be separately added elements or, alternatively, the stretch-resistant member(s) can be formed by modifying the absorbable material, for example by heating or soldering selected locations of the absorbable vaso-occlusive member, e.g., by soldering lines on the exterior or interior of a tube-shaped member or by heating or soldering one or more winds of a helically shaped member to connect at least two of said helical winds. In certain aspects, the stretch-resistant member comprises a mono-filament, for example polypropylene. In other embodiments, the stretch-resistant member is a multi-filament.
Any of the vaso-occlusive members described herein can further comprise a deployment tip, for example attached to at least one of the first end and second end of the member (e.g., coil or tube shape). The deployment tip can be, for example, an electrolytically detachable end adapted to detach from a pusher by imposition of a current on said pusher. Further, any of the vaso-occlusive members described herein can further comprise a radio-opaque material (for example powdered tantalum, powdered tungsten, bismuth oxide, and barium sulfate) and/or a bioactive material.
In yet another aspect, a method for producing a vaso-occlusive member is described comprising the steps of (i) preparing a generally linear primary element comprising an absorbable material; (ii) winding said primary element onto a mandrel; and (iii) heating said mandrel and said primary element to produce said three dimensional member (e.g, a 15 minute heating step at approximately 165xc2x0 C.). The vaso-occlusive member can have a variety of three-dimensional configurations including, for example, a helical coil configuration, a conical shape or a spiral shape. Further, any suitable mandrel can be used, for example, a stainless steel mandrel.
In yet another aspect, the invention includes a method for producing a vaso-occlusive member comprising the steps of preparing a tube-like structure comprising an absorbable material, for example by micro-machining.
In any of the methods described herein, the absorbable material can be, for example, polyglygolic acid (PGA), poly-glycolic/poly-L-lactic acid co-polymers, polycaprolactone, polyhydroxybutyrate/hydroxyvalerate copolymers, poly-L-lactide, polydioxanone, polycarbonates, polyanhydrides, collagen, elastin, fibrinogen, fibronectin, vitronectin, laminin, gelatin and combinations thereof.
Any of the methods described herein can further include the step of fixedly attaching one or more stretch-resistant members to two or more locations on the vaso-occlusive member, for example by knotting, heating or soldering the stretch-resistant member to the device or by heating, soldering, or plasticizing portions of the device to each other. In any of these methods, the stretch-resistant member can be either absorbable or non-absorbable. Furthermore, the stretch-resistant member can be a mono-filament, for example, polypropylene or a multi-filament.
In any of the methods described herein, the vaso-occlusive member can further comprise one or more radio-opaque material, for example, powdered tantalum, powdered tungsten, bismuth oxide, and barium sulfate and/or one or more bioactive materials.
These and other embodiments of the subject invention will readily occur to those of skill in the art in light of the disclosure herein.